A display device including a display screen formed by a light emitting element using an electro luminescence (hereinafter also referred to as EL) material has been developed. There are known a plurality of driving methods and panel configurations for such a display device. For example, known is a technology where a light emitting element for monitoring temperature is provided in a panel so that a constant current is supplied to a light emitting element of a pixel even when the ambient temperature varies (see Patent Document 1, for example).
Another display device is also disclosed, which includes a display panel formed by a plurality of light emitting portions, a driving means for supplying a constant current driving signal in accordance with an inputted signal, a detecting means for detecting a voltage generated in the light emitting portions, and a control means for controlling the constant current driving signal in accordance with changes in the voltage (see Patent Document 2, for example). In this display device, even when luminance is reduced due to degradation of a light emitting element, the voltage of a signal electrode connected to the light emitting element is detected by the driving means and a current from the driving means is increased so as to keep the luminance constant.    Patent Document 1: Japanese Patent Laid-Open No. 2002-333861    Patent Document 2: Japanese Patent Laid-Open No. 3390214